A tunable and reduced size power divider using ferroelectric thin-film varactors

Lourandakis, Errikos; Schmidt, Matthias; Leidl, Anton; Seitz, S.; Weigel, Robert

doi:10.1109/mwsym.2008.4632995

Cited by 16 publications

(6 citation statements)

References 8 publications

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“…From (9), the varactor values for the targeted frequency region are calculated. For Wilkinson divider prototype at bias state U = 6 V. Data from [14]. in [14] excellent agreement between simulation and measurements is obtained by using the equivalent varactor models from [28].…”

Section: A Wilkinson Dividermentioning

confidence: 62%

“…In this frequency region there are several communication bands allocated, thus frequency selectivity is desired. As discussed in [14], compared to a reduced size power divider with fixed capacitors improved isolation is achieved at the other operating bias states. All figures reveal the inherent low-pass behavior, thus harmonic radiation would be suppressed significantly when considering an operation in a transceiver front-end system.…”

Section: A Wilkinson Dividermentioning

confidence: 99%

“…Furthermore, active microwave circuits such as tunable voltage controlled oscillators [10], [11] and dynamically tunable power amplifiers [12], [13] have been reported. Previously we presented a reduced size and tunable power divider [14] based on BST-varactors. In this paper this new technique is generalized and applied to both, the Wilkinson divider [15] and the hybrid branch-line coupler.…”

Section: Introductionmentioning

confidence: 99%

“…Measured transmission and reflection S-parameters for tunableWilkinson divider prototype at bias state U = 17 V. Data from[14]. the implemented prototype varactors with nominal capacitance pF serve as tuning elements.…”

mentioning

confidence: 99%

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Reduced Size Frequency Agile Microwave Circuits Using Ferroelectric Thin-Film Varactors

Lourandakis

Schmidt²,

Seitz³

et al. 2008

IEEE Trans. Microwave Theory Techn.

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A new concept for tunable and reduced size microwave circuits is presented based on barium-strontium-titanate (BST) varactors. The proposed design methodology relies on substitution of quarter-wavelength transmission line segments with their equivalent low-pass structures. The ferroelectric BST-varactors are used as tuning elements and allow for a frequency agile behavior and size reduction of the circuit. Candidates for this methodology are quarter-wavelength based circuits such as Wilkinson power dividers and branch-line couplers. Prototype boards for both topologies were implemented and characterized through scattering parameter measurements. For the implemented Wilkinson divider a tuning range from 1.7 to 2.1 GHz is achieved. The insertion loss in both output paths varies from 0.6 to 1.2 dB while maintaining a worst case amplitude-and phase difference of 0.5 dB and 9 , respectively, for all operating cases. The isolation between the two output ports exceeded 25 dB over the whole tuning range. The implemented branch-line coupler exhibits a tuning range from 1.8 to 2.3 GHz with a maximum insertion loss of 2.7 dB while maintaining worst case amplitudeand phase difference of 0.4 dB and 90 5 , respectively. Port matching and isolation levels of more than 15 dB are exhibited at all bias conditions. Index Terms-Couplers, ferroelectric capacitors, power dividers, tunable circuits and devices.

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Section: A Wilkinson Dividermentioning

confidence: 62%

Section: A Wilkinson Dividermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Reduced Size Frequency Agile Microwave Circuits Using Ferroelectric Thin-Film Varactors

Lourandakis

Schmidt²,

Seitz³

et al. 2008

IEEE Trans. Microwave Theory Techn.

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“…The expanding wide frequency allocation of those standards and the worldwide varying regulations impose tight specifications since overall system efficiency and power consumption have to be optimized simultaneously. Tunable passive devices based on ferroelectric [1], [2] or MEMS components [3] have already proven their potential for use in reconfigurable systems, since they allow for implementations of tunable and frequency agile subsystems. So far, the properties of those components have been investigated mostly by academic research groups.…”

Section: Introductionmentioning

confidence: 99%

Characterization and Modeling of Continuously Tunable MEMS Varactor

Lourandakis

Fischer

Weigel

2009

2009 German Microwave Conference

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In this work a circuit model for a continuously tunable varactor is presented which is based on a microelectromechanical system (MEMS). This behavioral model can be implemented in commercially available simulation tools and allows for complete circuit simulations in terms of small-and large-signal performance, as well as for transient and envelope responses. For the present implementation Agilent's ADS is used but the modeling methodology can be generalized for use in other tools as well. For the MEMS varactor which is investigated in this paper good agreement is obtained between simulated and measured data. The capacitance variation for different tuning voltages as well as the frequency and power dependency of the component are discussed. For a bias voltage range up to 130 V a capacitance tuning ratio of more than 5:1 is obtained. The excellent linearity provided by minimal self actuation effects qualify the component for use in high power applications.

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Colossal Permittivity Materials as Superior Dielectrics for Diverse Applications

Wang

Jie

Yang

et al. 2019

Adv Funct Materials

156

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Ever since the beginning of this century, many kinds of materials have been reported to demonstrate colossal permittivity (CP) or colossal dielectric constant exceeding 10 3 . Accordingly, such CP materials and their further modification and improvement to achieve enhanced CP performance for promising applications in modern electronics, sensors, energy storage, and multifunctional devices and so on have attracted extensive attention. In this review, 2 a general overview of the recent advances in CP materials is provided, ranging from their various categories, physical mechanisms, and modulation methods to promising applications.First, various classes of CP materials are categorized in terms of their structures and dielectric properties. Subsequently, this review provides an insight into the CP mechanisms in views of barrier layer capacitance, defect-dipole cluster and polaronic effect. Moreover, the strategies and prototypical works are introduced in some aspects, including the manipulation of CP properties by doping, percolative capacitors and the methods employed to enhance the dielectric behaviors in CP materials with different forms. We then discuss a wide range of applications based on CP materials, such as modern electronics and energy storage. Finally, the challenges and opportunities for further investigation of CP materials are highlighted in the summary and future perspectives.

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A tunable and reduced size power divider using ferroelectric thin-film varactors

Cited by 16 publications

References 8 publications

Reduced Size Frequency Agile Microwave Circuits Using Ferroelectric Thin-Film Varactors

Reduced Size Frequency Agile Microwave Circuits Using Ferroelectric Thin-Film Varactors

Characterization and Modeling of Continuously Tunable MEMS Varactor

Colossal Permittivity Materials as Superior Dielectrics for Diverse Applications

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